The interrelated problems of disposing of human and animal sewage as well as industrial liquid-containing waste, and on the other hand of obtaining continuous and abundant supplies of pure water for both human consumption and industrial-agricultural use are so universal and omnipresent as not to require detailing or even enumeration. Although many approaches to the problems have been tried and to limited extents utilized, basic obstacles remain, such as economics of operation, availability of reagents and facilities, disposition of undesirable products from such operation, etc.
A process and apparatus for treating waste water from domestic sewage which employed sulfur dioxide gas and scrap iron for this purpose was disclosed by the present inventor in his U.S. Pat. Nos. 3,521,752 and 3,522,173, both issued July 28, 1970. To a certain extent the present invention may be considered an improvement of the process and apparatus there disclosed. The procedure as then developed, depended upon controlled admixture and regulated acidity obtained in the primary reaction chamber through the use of a horizontally elongated vessel through which the feed stock passed lengthwise while a mixture of gaseous oxygen and sulfur dioxide was concurrently ejected under pressure from perforations of a manifold disposed lengthwise within the chamber. This manifold with its gaseous mixture was continued into a second reaction chamber which contained scrap iron and received the flow of feed stock from the primary chamber. The treated fluid then continued through neutralization, settling and filtering steps.
As shown in the applicant's preceding patents, as well as in the earlier sulfur dioxide-iron oxidative process described by Urbain and Stemen in U.S. Pat. No. 2,171,203, it was considered essential that the gaseous stream of sulfur dioxide include gaseous oxygen (air). Further, problems have arisen by failure to obtain complete oxidation of solid material on the one hand, and alternately of premature precipitation, such as that of oxidized carbon which attaches itself to pieces in the iron bed so as progressively to stifle the flow.